I'm about to run out the string on my 535i CPO warranty, and have made it to 90k without any problems with the original turbocharger.

Now I'm looking at planning for the next phase of preventative maintenance work as I close in on the first 100k and get set up for the second. I have a couple little performance treats in mind, too - some new inlets are very tempting right now.

The question of the moment as I work up the plan is turbo lifespan. I always said if they went, I'd replace them with RBs. I kind of had a mental expectation that the originals would likely be good for about 100k max and would need a refresh, like so many other things.

So at this point, what is the collective wisdom of the forum on expected lifespan for the N54 turbocharger and whether it would be prudent to treat it like a water pump and do a preventative maintenance swap rather than wait for it to go?

Is replacement definitely a when, rather than an if, issue for a long-term vehicle?